.TH Ungroup
.PP
Inverse of group
.SH Signature
.PP
.RS
.nf
ungroup(operand: Relation, rva: AttrName) \-> Relation
.fi
.RE
.SH Examples
.PP
.RS
.nf
ungroup(group(suppliers, [:city], :suppliers, allbut: true), :suppliers)
.fi
.RE
.SH Description
.PP
Computes the relation obtained by ungrouping a relation\-valued attribute
\fB\fCrva\fR\&. Ungrouping \fB\fCrva\fR leads as many tuples as in \fB\fCrva\fR, each extended
with the other attributes of \fB\fCoperand\fR\&.
.PP
\fB\fCrva\fR must be a relation\-valued attribute. It should not itself contain
any attribute whose name clashes with an attribute of \fB\fCoperand\fR\&.
.SH Implementation notes
.PP
This operator does not compile to SQL so far. Contributions are welcome
to provide it with a SQL compilation for SQL DBMSs that support this kind
of feature (e.g. PostgreSQL with JSON data type)